OLT Express Poland announced Friday afternoon it has stopped all domestic operations, leaving thousands of passengers stranded. More than 6,500 passengers have been affected; up to 130,000 passengers will not be able to travel on the carrier’s domestic flights in the summer high season for the coming weeks.

The airline owner, Polish investment company Amber Gold, established OLT Express last year and also owns its sister company, OLT Express Germany. Amber Gold this week said it will sell parts of the company, leaving its future uncertain.

The carrier said on its website that all charter flights will operate according to schedule. OLT Express Poland may lose its air operators certificate after Polish aviation authorities criticized the carrier for not filing its financial data for 2011. The authority had set an ultimatum to deliver the data by July 31.

OLT Express Germany, which recently finalized the acquisition of Stuttgart-based Contact Air ( ATW Daily News, July 19 ), said it is already in talks with potential investors.

Originally we planned to develop the German market together,” which is the reason it wanted to create a joint brand. “Nevertheless, we continue our solid expansion plans with all power,” OLT Express Germany MD Joachim Klein said in a statement Friday.

“After our integration of Contact Air and we nearly completed our future business model, we are actually able to operate on its own (without Amber Gold and OLT Express Poland). Our assets create a well established company and I trust we can develop our company further,” Klein said.